A liver function test, is one of a standard range, of blood tests carried out, it is usually U&Es, LFT, Thyroid function, and Creatanine. The fact that it has come back, with a raised reading. does not necessarily mean, there is a problem, directly related, to the liver, it could be that, it is just showing up, in the liver. If your GP, was concerned, about the levels, you would have no doubt, been called back, in, to discuss, the high readings.
They always do, a liver function test, because the liver, has to metabolise medications, and clear the blood, of other impurities.
My liver function test, always comes back raised, due to thirty years, of taking, heavy doses, of ant depressant, medication.
If you are still worried I suggest you make an appointment with your GP to discuss the results